


Rule Breaker

by Jeb



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, F/M, I am also bad a titles, I'm also bad at smut, I'm really bad at descriptions I'm sorry, Shameless Smut, underfrick
Language: English
Status: Completed
Published: 2016-02-12
Updated: 2016-02-12
Packaged: 2018-05-19 20:33:00
Rating: Not Rated
Warnings: Rape/Non-Con
Chapters: 1
Words: 3,654
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5980213
Author URL: https://archiveofourown.org/users/Jeb/pseuds/Jeb
Summary: <blockquote class="userstuff">
              <p>You knew the rules, and you knew them well.</p>
            </blockquote>





	Rule Breaker

**Author's Note:**

> Whoops, sorry for this. I don't know how to write smut. Sorry!

"*Can you feel my fingers inside of you?" His gruff voice chased you from your thoughts, causing you to look back at him before remembering your place. You bit your lip and stared hard at the ground, not daring to break your concentration from the slab of concrete directly in front of you. Sans didn't usually talk when he used you like this, but that shouldn't be the catalyst for you breaking some of the rules he had set sometime ago. 

His phalanges, the ones belonging to the hand not currently probing your entrance, pinched and squeezed at your flesh. They didn't linger anywhere for more than a few seconds, grazing your stomach and then your thighs and then your arms, anywhere and everywhere he could get them. He was surprisingly gentle, as gentle as this sadistic monster could be, that is. It still hurt if you focused on the pain for too long, but he wasn't drawing blood. 

Yet. You reminded yourself that Sans was probably waiting for you to slip up. "*Hm?" You didn't answer. You knew better than to answer. His hand grabbed desperately at the flesh hanging over your ribs, you having grown a great deal skinnier since your capture, and squeezed hard. You took in a sharp gasp, but still didn't rouse to his bait. "*Kiddo, you gon'a answer me when I talk t'a you?" Your lips wiggled as he thrust his fingers deeper into you, curling the two phalanges in an attempt to disturb you. 

You felt his hard bones scraping along your tender flesh, the friction causing shivers of delight sparking from your quivering pussy now that you had noticed it. You stiffened the urge to grind against him, falling for that need earlier on had discouraged your actions after receiving the heavy punishment. Your ragged and chapped lips were torn even further as you bit into them, blood spurting from the freshly opened wound. You didn't let out so much as a squeak, even as he began to piston his fingers inside of you. 

"*C'mon, kid, throw me a bone, here." You closed your eyes and imagined that you were breaking away from his hold, away from him. You imaged returning home to your loving family and friends, to your wonderful pets and your amazing studies. You had been so spiteful before coming here, enough that you neglected most of those things when they no longer interested you, but both Sans and Papyrus had forced a new appreciation for the simple things. "*Hey, I say you can close your eyes?" 

You tore your eyes back open and returned your stare again to the floor below you. "*Heh. I was just joshin'." You didn't close your eyes. He was moving faster now, no doubt wanting to elicit some sort of response for you. No, you had enough scars. You had become wise to his and Papyrus' tricks, you could not be fooled easily. You tried to distract yourself again with thoughts of the past, but Sans didn't appear willing to let you disappear just like that. 

His hand left your still-dry entrance, your body not betraying your emotions for once, in favor of reaching it around you. With his free hand, he pushed on your back until your hands dragged against the cold floor and your knees quaked with the sudden stretch. "*Better." He growled, leaning into you so that his ribs pressed into your skin. You felt his hands drift over your curves, occasionally groping a handful of flesh for a moment before carrying on. 

He touched everywhere. He started at your stomach and moved down, careful to touch every inch of skin that he could without moving his position over you. He tugged at your thighs, he twisted your nipples, he tweaked your cheeks and played with your lips. He ran his hands through your hair, he traced along your neck and down your vertebrae, he left almost no place untouched. "*Answer me when I talk to you, got it?" You stayed silent, and as if it dawned on him now just how he had been treating you for who knows how long, you had lost count of time when the days grew into months, "*I'm not going to hurt you." 

You doubted that. He had never been so gentle, his words had never held so little malice, but you didn't believe him. He didn't give you a reason to. His arms wound around your middle and his hands parted your thighs further, allowing both hands access to your now wet entrance. He relished in the feeling of your bodily fluids coating his fingers, but did not press into you. You suspected that he was waiting until he had become aroused enough to ravish you with his cock instead of his fingers, he never took amusement in pleasing you. Quite the opposite, actually. 

His fingers brushed over the hood of your clit, trying to gain a response from the mound. Your body, which had began to betray you just by allowing some sort of arousal, reacted almost instantly to his ministrations. You tried to bring yourself away from this moment, tried to escape reality for just a little bit longer, but something about right now kept you grounded. You were forced to endure as he ran his phalanges over your slick folds, parting them and squashing his fingers against your mound with reckless abandon. He was going fast, too fast, and that made it just a little bit easier to deal with. 

You didn't like this. It was too rough, it was too quick, he didn't know what he was doing and he didn't care. "*D'you like this, kid?" He grunted, his ribs pressing even more into your flesh as he bucked his hips against your butt. It was very clear who was really enjoying what he was doing. When you didn't respond, he gripped at your mound tightly, the force sending unpleasant waves of pain to course through your body. 

Feeling as though you no longer had a choice, you went against what you had become to associate with as law and opened your mouth. Your voice sounded gross with disuse, and it was. You were never allowed to speak, never allowed to make any sort of noise, it only made sense that you sounded as though you had never spoken before. It took a few tries before you could articulate properly, the action of speaking feeling foreign now, and Sans had been surprisingly patient. He had released the death grip he had held on your clit, taking care to rub it gently and try to prompt your words. "No," You were honest, Sans knew when you were lying so you didn't try to. "I don't like it." 

You expected him to let out a guttural groan then, your pain usually causing him great amounts of pleasure. Today was obviously not a normal day. "*What don't you like? Tell me what you want." His voice was deep and his words sharp, but his tone lacked the hatred that you had become accustomed to. 

Still, as shocked as you were, you did not want to feel him grip your clit again. "I don't know." Your voice crackled and broke in pitch, but you got your message across. 

Knowing that you were telling the truth, Sans allowed a hand to part from where it had been holding your thighs open. Still using the other hand to rub gentle circles around your sensitive nub, he began to pump his fingers into you. He started with one, but when he noticed that you were almost wet enough to warrant a second, he thrust two more into you. "*Do you feel my fingers inside of you?" He asked, his voice coming out in a low grunt. He really was enjoying this. 

You knew he didn't care for snide remarks, but this moment was much too tender for Sans, and so you knew you had to be dreaming. You must have come a long way from home if your dreams were still filled with the same sadistic skeletal monster who haunted your days and ravaged your nights, his image stealing away your only reprieve. "It would be hard not to." 

"*Heh. Ya feel this?" He curved his fingers inside of you, curling them. You immediately bit your lip to stop any sounds that may have escaped, and hearing his dark chuckle next to your ear let you know that you hadn't been able to stop all of them. "*D'you like this, kiddo?" 

Your cheeks did not burn nor did you flush with embarrassment. This had happened too many times for you to find anything embarrassing about your situation. Unpleasant, yes. Embarrassing, it could no longer be. "No." You resisted the urge to close your eyes, even as the fingers prodding at your clit began to increase in pace, digging slightly into your flesh. 

"*No?" Sans rocked his hips into your thighs, his gym shorts feeling sticky against your sweaty skin. His fingers halted and you nearly let out a whine when he removed them. Gripping your hips with both hands, he allowed a soft grind against your entrance, his voice thudding in your skull as he spoke, "*I know your body better than you do, kiddo." His fingers were back at your pussy before the sentence even ended, one hand staying on your hip to steady you. He ran his fingers along your folds slowly before diving two phalanges back into your core, the sensation rocking through you in a way that was in no way unpleasant. Suddenly, his teeth were very close to your ear, the sound of his voice sending tremors through your body, "*I bet I've touched you more times than you've touched yourself." 

Your fingernails scraped along the concrete, sending shivers down your spine. It felt like nails running down a chalkboard. 

His dark laughter filled your mind for a moment, his voice getting rid of muddled thoughts once it began. You had learned to pay attention when he spoke. "*You like this, kid. Now, let me know just how much you like it." He punctuated the last sentence with a hard thrust into your entrance, his fingers wiggling inside of your core. You felt him against your inner walls, you felt his warm bones against your back and on your clitoris. "*Let me hear you." 

It wasn't a question, but you had decided that this most definitely was a dream and so you weren't going to listen. You kept your mouth shut even as your knees began to give out. His left arm snaked around your waist to hold you up, the phalanges of his right hand still pumping into you while the heel of his right palm dug against your clit. You felt his sharp teeth scrape along the skin of your neck, preparing yourself mentally for the pain that always followed. 

It never came. He pulled out of you again, just for a moment, before slamming back into you. The force sent you stumbling, but he was quick to catch you. Pulling at you until you were again in a standing position, Sans moved his left hand up your body until it rested against your cheek. "*I want to hear you, kid." His phalanges, still coated with your fluids from when he had used that hand to touch you, tugged at your lips. You released your bottom lip from where it had been resting in between your teeth when he began to pull too hard. 

Your eyes bugged and you puffed out your cheeks when he ran his tongue along the side of your neck. He was never this gentle before, but you should stop questioning it. Not every dream made sense. Most dreams didn't make sense. 

His maw opened and his teeth dug lightly into your skin, but not enough to draw blood. You squirmed against him, the action earning a throaty hum of pleasure from Sans, and you allowed one to escape passed your own lips when he began to worm his fingers against your more sensitive spots. Still holding your lip, he spoke almost happily, "*That's it. I told you, I know your body better than you do. Let me know just how much better I am, let me know just how much more than you I know." His phalanges dug deeper, scraping and playing within you in a way that elicited no other response but a short groan. "*Let loose, kid. I'm not going to hurt you. I want to hear you." 

He let go of your lip, giving you enough time to wet the flesh with your tongue before he pumped into you again. The tips of his phalanges were touching places that you could never possibly hope to reach, toying with you in a way you would have deemed cruel if you didn't know who was pressing into you. This was torture. You let out a quiet squeal of delight as his thumb began to move around your clit and apply pressure to the bundle of nerves, the sensation causing you to almost collapse. 

He brought his hips back to yours as he humped you almost erratically, the sound of your moan enough to weaken him. You looked back, tongue lolling from beyond your lips, and met his eyes with your own. You were quick to turn away, not forgetting your place even in your dreams, but he was quick to grip your chin and force you to face him again. Your neck strained and you felt your bones crack with the pressure, but the pain was quickly dismissed as the phalanges inside of you found a particularly sweet spot and began to focus on that. You were letting out almost desperate noises, now, still containing yourself enough to keep the volume almost muted. 

You huffed and panted, his hand moving you to a shivering mess. You hadn't had an orgasm in so long, Sans was careful to never allow one, but you were close now. "*What's my name?" His tone of voice carried a sudden seriousness that snapped you back to attention. His hips were steadily rocking against yours now, no longer sporadic and desperate, but his fingers were working against your flesh in a way that betrayed his want to bring you to release. When all you could do was release an unintelligible moan, he repeated again, "*What's my name?" 

You felt saliva slicked your tongue as you bit down hard on your cheek. You could see the glow of something red, you could feel something thick and slimy press against your back side as Sans rubbed himself against you. You knew he wanted nothing more than to bury his cock deep into your pussy, he wanted to sink into you and pump until he brought himself to his own release, but he was waiting. You maintained eye contact until he pressed almost unbearably hard against your clit, twisting and tugging the soft nub with almost cruel intentions. 

You allowed yourself to forget the rules for just a moment as your orgasm crashed over you. It was powerful enough to make your knees give out, and you let out a strangled "Sans!" as you lost yourself. 

You were shaking even after he cooled you down, his arms holding you up and his hands petting your sides softly. He waited until you had almost stopped shivering before he bent you over again, your hands slamming painfully against the stone as that red glow became all you could see. His cock slid into you without hesitation, your wet opening providing an easy entrance for his cock. He began to hump you with reckless abandon, your still-too sensitive nerves bundling up inside of you. You tried to let him know that it was too soon, you weren't ready, but all he did was laugh. "*What's my name, kid?" 

"Sans!" It sounded almost like a sob coming from your lips, but you hadn't cried in a long time. "Sans!" You repeated, closing your eyes and blocking out that wonderful red glow for just a moment before a hand bunched up your hair and pulled at the mass of tangles. You let out a startled yelp, feeling everything as his pelvic bones began to grind hard into your dry skin. You immediately began to reprimand yourself, you had so foolishly forgotten the rules, you deserved to be punished. 

"*Say it again!" He demanded, crashing into you with ease. 

Sickening squelching sounds were coming from behind you every time your bodies joined, the noise enough to cause your stomach to turn inside of you. Still, you complied, "Sans, Sans!" You panted like the dog you were, your head dropping forward as he threw it away from his fingers. 

You stared at the ground in front of you, noticing for the first time the small wet spatters that had begun to appear. Another one was form as Sans thrust deep inside of you, forcing you forwards. The motion had been enough to cause one of the tears running down your cheeks to abandon its preset track and plop onto the ground. 

You watched those little wet spots for a while, focusing on the old ones as they began to dry and the new ones as they dropped from your eyes. You were sobbing quietly, not making the mistake of uttering a sound again. You didn't even notice as two orgasms waved over your person, too focused on those droplets to have even that break your concentration. 

The heat of his fluids as they splurged inside of you brought you away from your self-destructive thoughts, though. He released his grip on you, but before he could throw you away from him you stumbled forwards. 

You knew what came next. You turned quickly and dropped to your knees, and Sans not missing a beat pressed the head of his cock to your lips. The tears were raining openly from your eyes now, and you had a feeling that it would be a long time before they stopped now that they had started. You took his member into your mouth readily, pointedly ignoring the thick sludge sliding from your opening and splattering onto the floor and coating your thighs. Your skin was sticky with sweat and your breath was heavy, but soon the latter of those two problems was erased. Your breath couldn't be heavy if you couldn't breathe, and with Sans' magic filling our mouth in the form of a grossly thick cock there was no way you were going to be breathing soon. 

His magic matted your hair even more and stuck around the corners of your lips as he pounded into you. "*Told ya I wasn't going to hurt you." You felt your eyes sting even more than they had been as he grabbed the back of your head and forced you to take more of his cock. "*But I didn't say nothin' 'bout Pap." You closed your eyes tightly as the magic began to ease its way all over your face. Your tears left dirty tracks through the red aura, dripping onto the floor with audible splats. 

"*'sides, he's usually the one who deals with rule breakers." You knew he was staring at you knowingly, but you didn't dare open your eyes. You forced labored breaths through your nose as you sucked dutifully on the dick in your mouth, your body still thrumming with heat even after he had finished. You could almost see the sick grin on his lips as he continued, "*Criminals. Liked that noise you were making earlier, though." He forced you closer onto you had reached the base of his cock. Your nostrils were flaring as you tried to breathe, the size of his member successfully blocking your airway enough where you couldn't even breathe through your nose. "*Maybe I'll tell him to go easy?" 

He rocked his hips against your face, and with a few more erratic thrusts, you felt his thick slime slowly slide down your throat. He slammed against you once, twice, three times before he was done spurting. You didn't look at him as he pulled out of your lips with a loud popping sound, you just allowed your tears to fall from your cheeks. Of course this hadn't been a dream. When was the last time you had dreamed? You swallowed the last of the residue in your mouth, gulping it down with as much air as you could. This decision led you to a loud coughing fit that had you doubling over and gasping for the air you had been denied. 

As you greedily took in what you could, you felt Sans grab at your hair. You felt him bunch up a handful and slide it along his flaccid cock, rubbing away your saliva. You both knew he didn't need to do that, he could have just allowed his cock to fade away, but you knew he wanted to embarrass you further. 

Without another word, he blipped out of the room, leaving you alone. Still, you didn't open your eyes, instead huddling in a pool of magical cum and gross fluids. You gathered your knees to your chest and shivered. 

You knew the rules, and you knew them well. You also knew that breaking them would bring consequences that were inhumane and unjust, not that the brothers cared. You'd broken plenty over the course of however long Sans had decided to visit you. You had looked at him, you had made noises, you had spoken words, you had said his name, there were so many rules that you had broken. You were going to pay for them, possibly with your life depending on how kind Papyrus decided to be. 

You willed yourself to travel away to the past, fully knowing that when Papyrus came, he would not go easy on you.

**Author's Note:**

> Thanks for reading until the end! <3 <3 <3!!


End file.
